Important Safety Notice
Note. The descriptions and specifications contained in the service information were in effect at the time the service information was approved for publication.
Appropriate repair methods and procedures are essential for the safe, reliable operation of all motor vehicles, as well as the personal safety of the individual doing the work. This service information provides general directions for repairing vehicles with tested, effective techniques. Following them will help ensure reliability.
There are numerous variations in procedures, techniques, tools, and parts for repairing vehicles, as well as in the skill of the individual doing the work. This service information cannot possibly anticipate all such variations and provide advice or cautions as to each. Accordingly, anyone who departs from the instructions provided in this service information must first establish that they compromise neither their personal safety nor the vehicle integrity by their choice of methods, tools, or parts.
Notes, Cautions, and Warnings
As you read through the procedures, you will encounter NOTES, CAUTIONS, and WARNINGS. Each one is there for a specific purpose. NOTES give you added information that will help you complete a particular procedure. CAUTIONS are given to prevent you from making an error that could damage the vehicle. WARNINGS remind you to be especially careful in those areas where carelessness can cause personal injury. The following list contains some general WARNINGS that you should follow when you work on a vehicle.
- Always wear certified rubber insulating gloves and a face shield when working with the high voltage cables, components, and wiring.
- Before disconnecting high voltage cables the ignition key must be cycled to the OFF position for at least 5 minutes.
- Do not disconnect, disable, or touch high voltage components during the module reprogramming procedure because high voltage is present.
- When working with the high voltage cables, components, and wiring, position 4 orange safety cones around the corners of the vehicle to mark off a 1 meter (3 feet) perimeter around the vehicle.
- Always place the high voltage traction battery service disconnect plug in Servicing/Shipping position.
- Always wear safety glasses for eye protection.
- Use safety stands whenever a procedure requires you to be under the vehicle.
- Make sure that the ignition key is always in the OFF position, unless otherwise required by the procedure.
- Set the parking brake when working on the vehicle. Place the gear selector in PARK unless otherwise instructed for a specific operation. Place wood blocks (4 inch x 4 inch or larger) against the front and rear surfaces of the tires to help prevent the vehicle from moving.
- Operate the engine in a well-ventilated area to avoid the danger of carbon monoxide poisoning.
- Keep yourself and your clothing away from moving parts when the engine is running, especially the drive belts.
- To prevent serious burns, avoid contact with hot metal parts such as the radiator, exhaust manifold, tail pipe, 3-way catalytic converter, and muffler.
- Do not smoke while working on a vehicle.
- To avoid injury, always remove rings, watches, loose hanging jewelry, and loose clothing before beginning to work on a vehicle.
- When it is necessary to work under the hood, keep hands and other objects clear of the radiator fan blades.
Preface
This service information provides a step-by-step approach for diagnosing driveability, emission, powertrain and hybrid-electric control system symptoms. Before beginning diagnosis, it may be helpful to reference any Technical Service Bulletins (TSBs) information when this is available.
This service information is used in conjunction with the SYSTEM WIRING DIAGRAMS. Refer to the appropriate SYSTEM WIRING DIAGRAMS for vehicle specific wiring information and component, connector and splice locations.
The following is a description of the information contained in each of the ENGINE PERFORMANCE articles. .
Pinpoint Tests Article
All pinpoint tests are included in the Pinpoint Tests article. Never enter a pinpoint test unless directed there. When directed to a pinpoint test, always read the information included at the beginning of the pinpoint test.
Reference Values Article
the Reference Values article contains the Typical Diagnostic Reference Values charts. The technician will be directed to these charts from Pinpoint Test Z in the Pinpoint Tests article.
Acronyms and Definitions
Note. This acronyms and definitions listing contains technical terms applicable to Ford Motor Company products. It is not intended to be an all-inclusive dictionary of components and their functions. If a detailed description of a particular system or component is desired, refer to the applicable article for the specific vehicle being repaired.
4V: Four valves per engine cylinder
ABS: Anti-Lock Brake System
ABS_STAT: ABS system status TCM received PID
A/C: Air Conditioning
A/CC: Air Conditioning Clutch
A/CCR: A/C Clutch Control Relay
A/CLPCS: A/C Low Pressure Cycling Switch
ACCS: Air Conditioning Cycling Switch
ACD: Air Conditioning Demand. A signal input to the PCM from the air conditioning control panel.
ACDS: Air Conditioning Diagnostic Switch (refrigerant containment switch)
ACET: Air Conditioning Evaporator Temperature (may also be referred to as Evaporator Air Discharge Temperature)
ACFDS_B: Air Conditioning Full Demand Switch (for traction battery compartment)
ACFDS_P: Air Conditioning Full Demand Switch (for passenger compartment)
ACP: Air Conditioning Head Pressure or A/C cycling switch input state
ACPSW: Air Conditioning Pressure Switch
ACPT: Air Conditioning Pressure Transducer (switch)
ACP V: Air Conditioning Pressure Volts. A voltage input to the PCM from the ACP switch or sensor.
ACRDV: A/C Refrigerant Distribution Valve Output
ACRDV_F: A/C Refrigerant Distribution Valve Output Fault
A/D: Analog-to-Digital. Analog-to-Digital signal conversion.
ADC: See ATDC.
Air/Fuel Ratio: Air-to-fuel mixture ratio. An air-to-fuel mixture that is 14.7:1 is also called stoichiometry.
Ambient Air Temperature: Temperature of the air surrounding an object
AMC: Active Mount Control
AMC_F: Active Mount Control Fault
Analog (Electrical/Electronic): An electrical signal that can obtain any value within the voltage limits of the signal.
APP, APP1, APP2, APP3: Accelerator Pedal Position 1, 2, 3
APPS, APPS1, APPS2, APPS3: Accelerator Pedal Position Sensor 1, 2, 3
ARB: Air Resource Board
ARPMDES: Desired engine speed TCM received PID
ASCII: American Standard Code Information Interchange
ATDC: After Top Dead Center. The location of the piston after it has reached the top of its stroke. Measured in degrees of crankshaft rotation.
AWD: All-Wheel Drive
BARO: Barometric Pressure
Base Timing: Spark advance in degrees before top dead center of the base engine without any control from the PCM.
Battery Positive Voltage (B+): The positive (+) voltage from the battery or any circuit connected directly to the battery.
BATTEMP: Battery Temperature
BJB: Battery Junction Box
BOB: Breakout Box. A test device which connects in series to the PCM and PCM harness.
BPA: Brake Pedal Applied. Typically located on the braking system master cylinder. Can be hydraulic or electric.
BPO: Battery Power Off
BPO_Hz: Battery Power Off Frequency PID
BPP: Brake Pedal Position
BPS: Brake Pedal Switch/Speed Control Deactivation
BRAKE_LMP or BRKL: Brake Warning Lamp Status. Activates the brake warning lamp by applying voltage to the control line.
BSI: Brake Shift Interlock
BTDC: Before Top Dead Center. The location of the piston before it has reached the top of its stroke. Measured in degrees of crankshaft rotation.
Bus + or Bus -: Multiplex circuits that carry controller area network (CAN) data from module to module and to the data link connector (DLC).
BVREF: Buffer Voltage Reference. A dedicated circuit that provides approximately a 5 volt signal used as a reference by certain sensors.
CAFE: Corporate Average Fuel Economy. A set of federal requirements and regulations which govern fuel economy standards.
CANVNT: Canister Vent
CAN: Controller Area Network
Catalyst: Catalytic converter. An in-line exhaust system device used to reduce the level of engine exhaust emissions.
CAT EVAL: Catalyst System Evaluated. This item indicates YES when the catalyst efficiency monitor has successfully completed.
CCM: Comprehensive Component Monitor
CCNT: Number of Stored and Pending DTCs
CD A through D: Coil Driver 1 through 4
Centralized Testing Facility: State government operation. Provides inspection/maintenance (IM) and safety inspections.
CGND: Case Ground. Provides a ground source for the PCM or ECU case.
CHT: Cylinder Head Temperature. Units are displayed in either degrees Fahrenheit or Celsius.
CHTV: Cylinder Head Temperature Voltage
CKP: Crankshaft Position
CKP_SHLD: Crankshaft Position Shield
CKP+, CKP-: CKP+ is the crankshaft position (CKP) sensor signal wire. CKP- is the signal return.
CL: Closed Loop. An operating condition or mode which enables operation based on sensor feedback.
CMP: Camshaft Position. PCM input signal from the camshaft position sensor.
CMPFM: Camshaft Position Failure Mode. Indicates when the PCM identifies a CMP fault.
CMS: Catalyst Monitor Sensor. The downstream HO2S.
CMVSS: Canadian Motor Vehicle Safety Standards.
CO: Carbon Monoxide. A colorless, odorless and toxic gas that is a component of auto exhaust emissions.
CO 2 : Carbon Dioxide. A colorless, odorless gas that is a normal by-product of the combustion of fuel.
Coil: A device consisting of windings around an iron core. In a spark ignition system, designed to increase voltage.
Cold Soak: Time given to a vehicle to sit at a low temperature, typically below 20 °C (68 °F), until the temperature of external and internal components stabilizes.
CONT: Continuous Memory. The portion of keep alive memory (KAM) used to store DTCs generated during the continuous memory self-test.
CONTACT: Traction battery contactor status TCM received PID
Continuous Memory Self-Test: A continuous test of the EEC system conducted by the PCM whenever the vehicle is operating.
COP: Coil On Plug. Ignition coil on plug assembly.
CPP Switch: Clutch Pedal Position Switch. Located on the clutch pedal and detects when the clutch pedal is pressed.
CQIS: Common Quality Indicator System
CRK_T: Time since engine started PID
CSE GND: Case Ground
CT: Closed Throttle. A mode when the PCM varies the pulse width of the fuel injectors to obtain the air/fuel mixture appropriate for closed throttle operation.
CTO: Clean Tach Output
DC: 1. Direct Current. Electric current flowing in 1 direction. 2. Duty Cycle. The voltage measurement of ON time versus the full cycle period, expressed in percent.
DCE: DC/DC Converter Enable
DCE_F: DC/DC Converter Enable Fault
DCF: DC/DC Converter Fault
DCL: Data Communication Link. A communication path between various in-vehicle electronic modules. Accessed by diagnostic tools through the data link connector (DLC).
Digital: Controls process information by switching the current or voltage ON and OFF.
DIS: Distributorless Ignition System. A system in which the ignition coil secondary circuit is sequenced without a distributor.
DLC: Data Link Connector. J1962 connector providing access to vehicle diagnostic information.
DMM: Digital Multimeter
DOHC: Dual Overhead Cam. An engine configuration that uses 2 camshafts positioned above the valves.
DRI: Deposit Resistant Injector. A fuel injector designed to prevent the build-up of carbon and other unwanted deposits.
DRIVECT: Number of completed OBD Drive Cycles PID
DTM: Diagnostic Test Mode. A level of capability in an OBD system.
DTC: Diagnostic Trouble Code. An alpha/numeric identifier for a fault condition identified by the OBD system.
ECT: Engine Coolant Temperature. Displayed in either Fahrenheit or Celsius.
ECTV: Electronically Controlled Continuously Variable Transaxle
EEC: Electronic Engine Control
EEC-V: Fifth-generation EEC system
EEPROM: Electrically Erasable Programmable Read Only Memory
EGR: Exhaust Gas Recirculation. A process in which a small amount of exhaust gas is routed into the combustion chamber.
EGR EVAL: Exhaust Gas Recirculation System Evaluated. EGR EVAL will display YES when the monitor is complete.
EGRMC (1-4): Electric Exhaust Gas Recirculation Motor Control
EGRMC_F (1-4): Electric Exhaust Gas Recirculation Motor Control Fault
EGRMDSD: Electric Exhaust Gas Recirculation Motor Desired Position. The PID name used to operate the EEGR valve with diagnostic tools output state control.
EGRT: Exhaust Gas Recirculation Valve Temperature. A temperature sensor that is threaded into the bottom of the intake plenum.
EI: Integrated Electronic Ignition. An electronic ignition system that has the ignition control module (ICM) integrated into the PCM.
EI-LDR: Electronic Ignition-Low Data Rate
ENG CTO: Vehicle speed TCM received PID
EMI: Electromagnetic Interference. Usually caused by ignition voltage spikes, solenoids, relay operation, or noisy generator contacts.
EOL: End of Line. A system designed specifically for use at assembly plants to make sure all new vehicles conform to design specifications.
EOT: Engine Oil Temperature
EPA: Environmental Protection Agency (United States Government)
EPROM: Erasable Programmable Read-Only Memory. An electronic component in the PCM that allows the electronic storage of information.
ESM: EGR System Module
ETC: Electronic Throttle Control
ETCVREF: Voltage Reference (5V) for ETC (APP BVREF, TP BVREF)
EVAP: Evaporative Emissions. A system to prevent fuel vapor from escaping into the atmosphere.
EVAPCP: Evaporative Canister Purge Solenoid. Controls a solenoid which allows venting of the evaporative purge canister.
EVAPCPF: Evaporative Canister Purge Solenoid Fault. Identifies whether an electrical fault exists for the current commanded state.
EVAPCV: Evaporative Canister Vent Solenoid. Controls a solenoid which seals the EVAP system canister from atmospheric pressure during the EVAP OBD Monitor test.
EVAPCVF: Evaporative Canister Vent Solenoid Fault.
Evaporative Emissions Canister: An evaporative emission canister containing activated charcoal which absorbs and holds fuel vapors.
EVAPPDC: Evaporative Canister Purge Duty Cycle. The duty cycle commanded to the EVAP canister purge solenoid by the PCM.
EVAPVMA: Evaporative Vapor Management Valve Internal Circuit Monitor
EVO: Electronic Variable Orifice
EVMV: Electric Vapor Management Valve. Also known as the EVAP canister purge valve.
Exciter Ring: A toothed or notched iron or steel disk which is the moveable part of a speed sensor.
FAN: Fan Speed
FC, FC1, FC2, FC3: Fan Control
FCS: Fuel Control Solenoid
FCIL: Fuel Cap Indicator Lamp. Indicates the fuel filler cap is not properly installed.
FEAD: Front End Accessory Drive
FEPS: Flash EEPROM Programming Signal. 18-volt DC signal sent by the diagnostic tool to initiate PCM reprogramming.
FLI: Fuel Level Input. Used by the EVAP monitor to calculate fuel tank vapor volume. Displayed as a percentage.
FLI V: Fuel Level Input Voltage
FMEM: Failure Mode Effects Management. Operating strategy that maintains limited vehicle function in the event of a PCM or EEC component failure.
FP: 1. Fuel Pump. Indicates whether the pump has been commanded ON or OFF by the PCM. 2. Fuel Pump (Modulated). Fuel pump duty cycle percentage.
FPC: Fuel Pump Control
FPDM: Fuel Pump Driver Module. A module that controls the electric fuel pump.
FPF: Fuel Pump Fault. Identifies whether a fault exists in the FP circuit.
FPM: Fuel Pump Monitor. Monitors the fuel pump/circuits for faults.
Freeze Frame: A block of memory containing the vehicle operating conditions at a specific time.
FRP: Fuel Rail Pressure
FRPT: Fuel Rail Pressure Temperature Sensor
FRP V: Fuel Rail Pressure Voltage. A voltage input to the PCM from the fuel rail pressure sensor.
FRT: Fuel Rail Temperature
FRT_V: Fuel Rail Temperature Voltage
FRTMPAB: Engine Fuel Temperature-Bank 1 Input
FSC: Fail-Safe Cooling
FTIV: Fuel Tank Isolation Valve
FTP: Fuel Tank Pressure
FTP V: Fuel Tank Pressure Voltage. From the FTP transducer
FUEL PR: Fuel Pressure. Measurement of the force of the fuel delivered by the fuel pump.
FUELPW: Fuel Pulse Width. Displays the commanded pulse width at time of last data update.
FUELPW1: Fuel Injector Pulse Width Number 1. Corresponds to injectors normally affected by HO2S11.
FUELSYS: Fuel System Status (OPEN/CLOSED Loop). Formerly known as LOOP.
Fuel Tank Vapor Valve: A valve mounted in the top of the fuel tank that vents excess vapor and pressure from the fuel tank into the evaporative emission control system.
FWD: Front Wheel Drive
GCLTEMP: Generator Motor Coil Temperature
GCU: Generator Control Unit
GENMODE: Generator Motor operational mode TCM received PID
GND: Ground
GPM: Grams per Mile. Also known as Gallons per Minute.
Green State Vehicle: Formally known as California Emissions. A vehicle that is equipped with California on-board diagnostics.
GSDN: Generator Motor Shutdown
G_SDN: Generator Motor Shutdown Request PCM PID
G_SDN_A, G_SDN_C: Generator Motor Shutdown Request TCM PIDs
G_SPEED: Generator Motor Speed
GTQ_CMD: Measured generator motor torque PID
GTQ_OUT: Desired generator motor torque TCM received PID
G_INV_V: Actual generator motor inverter voltage
G_PHTEMP: Highest of 3 phases generator motor inverter temperature
GVW: Gross Vehicle Weight
Hall Effect: A process where current is passed through a small portion of semiconductor material and a magnetic field to produce a small voltage in the semiconductor.
Hard Fault: A fault currently present in the system
HC: 1. Hydrocarbon. A by-product of combustion and a component of auto exhaust emissions. 2. High Compression.
HFC: High Fan Control
HFCF: High Fan Control Fault. Identifies if there is a fault in the HFC circuit.
HFPIP: PIP up edge to PIP down edge time
HLOS: Hardware Limited Operating Strategy. A mode of operation where the PCM replaces output commands with fixed values in response to internal PCM malfunctions.
HO2S: Heated Oxygen Sensor. Provides information on rich or lean exhaust conditions to the PCM.
Hot Soak: Period of time after an engine operates where localized combustion heat dissipates throughout the engine.
HPUMP: Heater Pump Control
HPUMP_F: Heater Pump Fault
HS-CAN: High Speed Controller Area Network
HTR, HTR11, HTR12: HO2S Heater. Heater element for the HO2S sensor.
HTR11F, HTR12F: HO2S Heater Fault
HV_AMP: Traction battery current TCM received through the communication network PID.
HVBAT_V: Traction battery voltage TCM received through the communication network PID.
HVIL: High Voltage Interlock Circuit
HVINTLCK: High Voltage Interlock Circuit Status PID
HVIN: High Voltage Interlock Negative Circuit
HVIP: High Voltage Interlock Positive Circuit
HVN: High Voltage Negative Circuit
HVP: High Voltage Positive Circuit
Hydrogen: Chemical symbol H. Highly flammable gas.
Hz: Hertz. Cycles per second
IAT: Intake Air Temperature
IAT_V: Intake Air Temperature Voltage. Actual voltage drop across the IAT sensor.
IC: Integrated Circuit. A small semi-conductor device capable of doing many separate circuit functions.
IFS: Inertia Fuel Shut Off
IGN GND: Ignition Ground
Ignition: System used to provide high voltage spark for engines
IGN_KEY: Ignition Key
IGN_OFF: Ignition Switch Position OFF Input PID
IGN_R: Ignition Switch Position RUN Input PID
IGN_R/S: Ignition Switch Position START Input PID
IGN_SW: Ignition Switch Position
IMAP: Inferred MAP
IMRC: Intake Manifold Runner Control. Controls or modifies airflow through the engine air intake system.
IMRCM: Intake Manifold Runner Control Monitor. Monitors the IMRC circuits for faults.
INJ1, INJ2, INJ3, INJ4: Injector number or its signal output from the PCM.
INJ_TIM: Injector Timing Before Top Dead Center
Injector: A device for delivering metered pressurized fuel to the intake system or the cylinders.
Intake Air: Air drawn through a filter and distributed to each cylinder for use in combustion.
IPC: Independent Plausibility Checker
ISDN1, ISDN2: Immediate Shutdown Circuits 1 and 2
I_SDN_1, I_SDN_2: Immediate Shutdown 1 and 2 PIDs
ISP-R: Ignition Switch Position RUN Circuit
ISP-R/S: Ignition Switch Position START Circuit
ISO: International Standards Organization
ITCC: Intelligent Torque Controlled Coupling
KAM: Keep Alive Memory. A portion of the memory within the PCM that must have power even when the vehicle is not operating.
KAPWR: Keep Alive Power. A dedicated and unswitched power circuit that maintains KAM.
KEYPWR: Key Power. Battery voltage supplied when the ignition key is in the ON position.
Knock: A sharp metallic sound produced when 2 combustion pressure fronts collide in the combustion chamber of an engine.
KOEO Self-Test: Key On Engine Off Self-Test. A test of the EEC system conducted by the PCM with power applied and the engine at rest.
KOER Self-Test: Key On Engine Running Self-Test. A test of the EEC system conducted by the PCM with the engine running and the vehicle at rest.
Km/h: Kilometers Per Hour
kPa: Kilopascal. Unit of pressure. 3.386 kPa equals 1 inch of mercury (Hg.)
KS1: Knock Sensor Bank 1. Detects engine knock.
L: Liters. The unit of volume in the metric measuring system. One liter equals 1.06 quarts.
LDR: Low Data Rate. Type of misfire monitor.
LFC: Low Fan Control
LFCF: Low Fan Control Fault
LOAD: Calculated Engine Load
LONGFT1: Long-Term Fuel Trim Bank 1. Fuel flow adjustment determined by the PCM.
LOOP: Indicates OPEN or CLOSED loop status.
LOS: Limited Operating Strategy
LOSSTRT: Limited Operating Strategy related to the engine no start condition
LOS_BRK: Limited Operating Strategy related to regenerative braking fault
LOS_ENG: Limited Operating Strategy related to the engine fault
LOS_ETC: Limited Operating Strategy related to the ETC system fault
LOS_EQ: Limited Operating Strategy related to the E-Quizzer detected fault
LOS_GEN: Limited Operating Strategy related to the generator motor fault
LOS_HV: Limited Operating Strategy related to the high voltage traction battery fault
LOS_IPC: Limited Operating Strategy related to the independent plausibility checker detected fault
LOS_KEY: Limited Operating Strategy related to the ignition key position fault
LOS_LV: Limited Operating Strategy related to the low voltage system fault
LOS_MOT: Limited Operating Strategy related to the traction motor fault
LOS_OWC: Limited Operating Strategy related to the one way clutch fault
LOS_TCM: Limited Operating Strategy related to the transaxle fault
LPLR: Low Pressure Low Resistance fuel injector
MAF: Mass Air Flow
MAF_V: Mass Air Flow Voltage
MAF RTN: Mass Air Flow Return. A return circuit for the MAF sensor.
MAP: Manifold Absolute Pressure. The internal pressure of the intake manifold.
MAP_V: Manifold Absolute Pressure Voltage
MCLTEMP: Traction Motor Coil Temperature
MCU: Motor Control Unit
MECT: Motor Electronics Cooling Temperature
MECT_V: Motor Electronics Cooling Temperature Voltage
MECP: Motor Electronics Cooling Pump Control
MECP_F: Motor Electronics Cooling Pump Fault
MECP_V: Motor Electronics Cooling Pump Voltage
MFC: Medium Fan Control
Microprocessor: A device that controls logic and arithmetic functions.
MIL: Malfunction Indicator Lamp. An indicator lamp alerting the driver of an emission related malfunction.
MISF: Misfire. Any event in the cylinder that causes a sudden change in acceleration of the crankshaft.
MSDN: Motor Shutdown
M_SDN: Motor Shutdown Request PCM PID
M_SDN_A, M_SDN_C: Traction motor shutdown request TCM PIDs
MTQ_CMD: Measured traction motor torque PID
MTQ_OUT: Desired traction motor torque TCM received PID
M_INV_V: Actual traction motor inverter voltage
M_PHTEMP: Highest of 3 phases traction motor inverter temperature
M_SPEED: Traction Motor Speed
MY: Model Year
NC: Normally Closed
NGS: New Generation Self-Test Automatic Readout (STAR) tester.
NO: Normally Open
NO X : Oxides of Nitrogen. Formed at high combustion temperatures.
O2S, O2S11, O2S12: Oxygen Sensor. Provides information on rich or lean exhaust conditions to the PCM.
O2S11SV, O2S12SV: Oxygen Sensor Voltage Input Pids.
OASIS: On-line Automotive Service Information System
OBD, OBD-II: On-Board Diagnostics, On-Board Diagnostics Second Generation. A system that monitors PCM input and output control signals.
On-Demand Test: The KOEO and KOER tests of the PCM and KOEO test of the TCM initialized by a technician.
OC: Oxidation Catalytic converter. A catalytic converter system that reduces the levels of HC and CO emissions.
OCT ADJ: Octane Adjust. Compensating strategy that adjusts for changes in fuel octane.
OEM: Original Equipment Manufacturer
OHC: Overhead Cam. An engine configuration that uses a single camshaft positioned above the valves.
Open Circuit: A circuit which does not provide a complete path for flow of current.
OL: Open Loop. An operating condition based on instructions not modified by PCM feedback.
OSC: Output State Control
OTM: Output Test Mode
OWC: One Way Clutch
Ozone: A blue gaseous form of oxygen (O 3 ) formed naturally by electric discharge or exposure to ultraviolet radiation.
PCM: Powertrain Control Module
PCV: Positive Crankcase Ventilation. A system which allows the controlled flow of crankcase vapors into the combustion chamber.
PF: Purge Flow. Amount of fuel vapor burned in the engine.
Photochemical: Term describing the action of light on air pollutants which results in creating smog.
PID: Parameter Identifier. Identifies an address in PCM memory which contains operating information.
PIP: Profile Ignition Pickup. Provides crankshaft position information for ignition synchronization.
PIP_CTR: PIP counter
PIPTIM: Last PIP time
Potentiometer: An adjustable resistance component commonly used as a sensor (example: TP sensor).
Powertrain: Engine and transmission/transaxle components.
Pressure - Absolute: A pressure referenced to a perfect vacuum.
Pressure - Atmospheric: The pressure of the surrounding air at any given temperature and altitude. Sometimes called barometric pressure.
Pressure - Barometric: Atmospheric pressure or the results obtained by a barometer.
Pressure - Differential: The pressure difference between 2 regions, such as between the intake manifold and the atmospheric pressure.
Pressure - Gauge: The amount by which the absolute pressure exceeds the atmospheric pressure.
PRNDL: Gear Selector Position
PRNDL_T: Gear Selector position TCM received PID
PPM: Parts per Million. A measure used in emission analysis.
PROM: Programmable Read-Only Memory. Similar to ROM, except without program instructions.
Protocol: A set of rules for the exchange of information on a network.
PSCM: Power Steering Control Module
PSR: Power Sustain Relay
PW: Pulse Width. The length of time an actuator, such as a fuel injector, remains energized.
PWM: Pulse Width Modulation. Controls the intensity of an output by varying the signal duty cycle.
PWR GND: Power Ground. The main ground circuit in the EEC system.
PZEV: Partial Zero Emission Vehicle
Quick Test: A series of diagnostic tests consisting of KOEO, KOER, and continuous memory self-tests. The resulting DTCs are retrieved using the diagnostic tool.
RAM: Random Access Memory. Memory into which information can be written as well as read. RDI: Restraint Deployment Indicator
REDOX: Reduction Oxidation Catalytic converter. A catalytic converter system designed to operate at high temperatures.
Relay: An electromechanical device in which connections in 1 circuit are opened or closed by changes in another circuit.
Repetitive Spark: Multiple firings of individual spark plugs at engine speeds below 1,000 RPM to improve idle quality and improve emissions.
RF: Radio Frequency
RFI: Radio Frequency Interference
RFS: Returnless Fuel System
RM: Relay Module. A module containing 2 or more relays.
ROM: Read-Only Memory. Computer memory that can be accessed and used, but not altered.
RON: Research Octane Number
Routine: A group of related tasks, such as a series of diagnostic tests.
RPM: Revolutions per Minute
RPMDSD: Desired engine speed
RTN: Return. A dedicated sensor ground circuit.
RWD: Rear Wheel Drive
SAE: Society of Automotive Engineers
SCCS: Speed Control Command Switch
SCP: Standard Corporate Protocol
Self-Test: See Quick Test
Sensor: A device that detects the value or change in a physical quantity, such as temperature, pressure, or flow rate, and converts the data into an electrical signal.
SFI: Sequential Multiport Fuel Injection. A multiport fuel delivery system where each injector is individually energized and timed relative to its cylinder intake event.
Shield: A conducting sleeve that surrounds wires to be electronically isolated from electromagnetic interference (EMI).
Short Circuit: An undesirable condition in a circuit where the circuit termination is at a point other than that intended.
SHRTFT1: Short-Term Fuel Trim Bank 1. Fuel flow adjustment in response to the HO2S sensor input during closed-loop operation.
SIG RTN: Signal Return. A dedicated sensor ground circuit that is common to 2 or more sensors.
Smart Driver: A PCM or ECU output driver that can detect faults (open or shorts) on its output circuit.
SME: Society of Manufacturing Engineers
SOC: State Of Charge
Solenoid: A device consisting of an electrical coil which produces a magnetic field which changes the position of a metal plunger.
Stoichiometry: An air/fuel mixture that is neither too rich nor too lean. Stoichiometric ratio is 14.7 parts of air for every 1 part of fuel.
Switch: A device for making, breaking, or changing the connections in an electrical circuit.
TACH: Tachometer
TACM: Throttle Actuator Control Motor used in the ETC system.
TB: Throttle Body. A device that controls airflow through the engine via a butterfly valve and has an air bypass channel around the throttle plate.
TBCM: Traction Battery Control Module
TCM: Transaxle Control Module
TCM_CAU: Caution indicator TCM commanded on.
TCM_HAZ: Hazard indicator TCM commanded on.
TDC: Top Dead Center
Tear Tag: The 2-piece adhesive label attached to the PCM to identify its calibration.
TFT: Transmission Fluid Temperature. Indicates the temperature of transmission fluid.
TGAC: Torque of Generator AC signal
Thermistor: A temperature dependent resistor used in CHT and ECT sensors.
Timing: The relationship between spark plug firing and piston position expressed in crankshaft degrees before (BTDC) or after (ATDC) top dead center of the compression stroke.
TMAC: Torque of Motor AC signal
TORQUE: Engine torque TCM received PID
TQ_DSD: Desired Engine torque TCM received PID
TP: Throttle Position Sensor. A potentiometer that provides throttle angle and rate information for the PCM.
TP V: Throttle Position Sensor Voltage
TP_MODE: Throttle Position Mode
TP_V: Throttle Position Voltage Input
TPB: Secondary Throttle Position Voltage Input
TPREL: Lowest steady TP voltage since engine start
TR: Gear Position Indicated By Transmission Range Sensor
TR-A Sensor: Analog Transmission Range Sensor. Provides information to the PCM on the transmission range selector position.
TR_A1, TR_A2, TR_A3: TR-A 1, 2, and 3 inputs
Transducer: A device that receives energy from 1 medium and transfers it to another. For example, thermal energy is converted to an electrical signal through a temperature probe.
TRIPCNT: Number of completed OBD trips
TSB: Technical Service Bulletin. Notifies the technician of any known vehicle concerns, procedures, or general repair information.
Underspeed M ode: A control mode that prevents the engine from stalling in the event it stumbles while running. Also used during engine crank.
Vacuum: Manifold pressure that is reduced below the ambient atmospheric pressure.
Variable Reluctance: A process of passing a varying magnetic field through wire windings and inducing a voltage.
VBPWR: Vehicle Buffered Power. A PCM supplied power source that supplies regulated voltage.
VC: Vehicle Certification
VECI: Vehicle Emission Control Information label
VEHMODE: Vehicle operational mode TCM received PID
VIN: Vehicle Identification Number. A unique identification number given to every vehicle produced. Includes information about the year, model, engine, and plant origin of the vehicle.
VMV: Vapor Management Valve. Controls the flow of fuel vapors out of the carbon canister.
VPWR: Vehicle Power. A switched circuit that provides power to the EEC system. Compare Battery Voltage (B+).
VREF: Reference Voltage. A dedicated circuit that provides approximately a 5 volt signal used as a reference by certain sensors.
VSC: Vehicle System Controller
VSS: Vehicle Speed Sensor. A magnetic pickup device that generates an AC signal that is proportional to the vehicle speed.
WAC: Wide Open Throttle A/C Cut-Off. Turns the A/C system off during wide open throttle or certain other operating conditions.
WOT: Wide Open Throttle. A condition of maximum airflow through the throttle body.
Zip Tube: Another name for fresh air duct or air inlet duct.